KR20220140849A - Apparatus, method and system for measuring position on an object - Google Patents

Abstract

A system for monitoring a survey reflector arranged at a plurality of positions on an object, comprising: a camera comprising: one or more light sources arranged to illuminate a field in space corresponding to at least 10% of a field of view of the camera, preferably the entire field of view; - an image sensor that receives a light beam from the reflection of the beam by a survey reflector and provides data; a camera comprising: a body having an optical entry system, an image sensor located on a first side of the body, and a light source located on a second side of the body; and a processing unit that processes the data. The processing unit is configured to determine a position of the survey reflector from the image sensor data and detect movement of the survey reflector based on a comparison of the determined position with the previously determined position.

Description

Apparatus, method and system for measuring position on an object

The present invention relates to a system and method for monitoring a position on an object. The invention may also relate to systems and methods for monitoring and/or detecting motion of an object.

Systems and methods for measuring the position of remote objects have long been known, for example, in the field of surveying and/or monitoring of structures.

WO 2019/143249 A1 and WO 2019/143250 A1 disclose devices and methods for monitoring the position of an object, eg a structure, over time. The disclosed system includes a beacon using an active light source positioned at a location to be measured. These publications suggest a solution for reducing the influence of interfering light sources such as ambient light and for the efficient identification of various beacons.

However, an active light source requires a power supply. For long-term monitoring, it may be necessary to use batteries, replace batteries, or harvest energy locally (eg, using solar panels).

US 2018/0224527 A1 describes a coordinate measuring device for detecting the position of a target object that can move in space, the device having an automatic target recognition function. However, the apparatus presents great complexity, and the measurement procedure will take some time when measuring a plurality of target objects.

US 8,553,212 B2 describes a geodesic measuring system and method for identifying a target unit having a geodesic measuring device. This publication focuses on the identification of target units. However, if a plurality of target units are to be measured and identified accordingly, the procedure appears to be relatively time consuming.

The problem addressed in this document is how to make it possible to monitor the position of an object over time. More specifically, the problem to be solved relates to monitoring an object, such as a building, which must have a fixed position relative to the earth but move over time. A position on an object may refer to a position that changes slowly over time, and even the object as a whole may undergo deformation. Causes are the soft ground on which the building stands, underground construction under the building (for example, to construct an underground parking lot or subway), and earthquakes (caused by, for example, extraction of natural gas from the soil location beneath the building) may be related to

More specifically, the task of the present invention is to overcome the shortcomings of the prior art and allow location monitoring over time while reducing power consumption and still providing efficient and reliable monitoring at monitored locations, particularly remote locations. . In particular, it is an object of the present invention to reduce the dependence on the power source at the monitored location.

Another object of the present invention is to enable more time-efficient monitoring of a position on an object.

Another object of the present invention is to reduce the complexity of a system and/or method for monitoring a position on an object.

Accordingly, the present invention provides a system as defined in independent claim 1 .

The invention also provides a method as claimed in the other independent claims.

Advantageous embodiments are claimed in the dependent claims.

According to a first aspect of the present invention, there is provided a system for monitoring a survey reflector arranged at a plurality of locations on an object, the system comprising:

As a camera,

one or more first light sources for emitting a first divergent beam, wherein the one or more first light sources are arranged such that a field in space corresponding to at least 10% of a field of view of a camera is illuminated by the one or more first light sources;

an image sensor for receiving a reflected light beam comprising reflection of the first divergent beam by the plurality of survey reflectors and providing data; and

a body provided with an optical entry system, the body having a first side facing an interior space of the camera and a second side facing away from the interior space, wherein the image sensor is located within the interior space, the one at least a first light source is located on the second side of the body, and wherein the at least one first light source is arranged at a first distance from the optical input system;

a camera comprising; and

a processing unit configured to process the data

including,

The processing unit determines a position of each survey reflector from the data, and is configured to: move one or more of the plurality of survey reflectors based on a comparison of the determined location of each survey reflector with a previously determined location of the survey reflector is configured to detect

Using one or more light sources to emit divergent beams may enable the camera to simultaneously capture images of a plurality of survey reflectors positioned apart from each other without moving the camera and/or without scanning the one or more light sources. do. The one or more first light sources are arranged such that a cumulative light beam generated by the first divergent light beam emitted by each of the one or more first light sources covers a field in space corresponding to at least 10% of the field of view of the camera. Thereby, all survey reflectors located within this 10% of the camera's field of view can be illuminated and thus monitored simultaneously.

Thereby, the need to move the camera to scan the light beam emitted by the camera to monitor the plurality of survey reflectors may be avoided. This is in contrast to conventional systems that typically use a collimated laser beam. Using a collimated laser beam has the advantage of providing high intensity light, but when provided in a camera for use with a passive reflector, it may be necessary to scan the camera to monitor multiple survey reflectors.

The one or more first light sources each emit a diverging beam, a beam whose cross-section has non-negligible dimensions in two dimensions. In a preferred embodiment, the first diverging beam exhibits a cone, preferably a right circular cone, with a first solid angle greater than 0°. Alternatively, the first diverging beam may represent an elliptical cone. Because the light intensity or luminous flux of the divergent beam decreases with distance from the light source, a high power light source, preferably a high power LED, is preferably used to maintain the desired working distance, i.e. the distance at which the survey reflector can be detected. should be used

In some embodiments, one first light source may be provided that emits a light beam having a solid angle large enough to cover at least 10%, or even more, of the camera's field of view.

According to one embodiment, the field in space corresponds to at least 50% of the field of view of the camera. In a preferred embodiment, the field in the space illuminated by the one or more first light sources is substantially equal to or greater than the field of view of the camera. In some embodiments, one first light source may be provided and the entire field of view of the camera is illuminated with the first beam. In another embodiment, two or more first light sources are provided, each assembly of divergent light beams substantially covering the field of view of the camera.

Thereby, the survey can be performed faster than in the prior art which relies on a scanning system. In addition, the complexity of the system is reduced since the surveying and/or monitoring of a plurality of survey reflectors can be performed without relying on a moving part and/or a plurality of cameras.

As described herein above, in a preferred embodiment, the camera may be provided with a non-refractive element, for example a pinhole, which serves as an objective. As described in WO 2019/143250 A1, this has several advantages, including reduced optical distortion compared to cameras using a refractive optical element forming the objective, ie one or more lenses. In particular, for a camera using a non-refractive optical element, compared to a conventional camera using a lens as an objective, among the following, it has the following advantages:

● pure geometric properties of the optical element;

● minimal or even no chromatic aberration;

● Nearly infinite depth of field;

● minimal thermal sensitivity due to the low thermal capacity and very low thermal resistance of the body provided with the optical input system;

● The angle of view depends only on the size of the image sensor and the distance between the pinhole or slit and the image sensor;

● Image sensor and optical input system can be reduced in size;

● Since the weight associated with the lens is avoided, it is very light in weight;

● Low cost as lens cost is avoided;

● Relatively simple calibration procedure.

It may be advantageous to have more than one first light source. If the optical input system includes one or more non-refractive elements, such as pinholes, the camera will be relatively sensitive to water droplets or dust on the survey reflector. This is because pinholes have an infinite depth of field. By providing the camera with a plurality of first light sources, the probability that the reflection of the first beam emitted by the camera will be negatively affected by disturbances on the prism can be reduced, which leads to a more robust system.

Power at the location to be monitored can be omitted by using a passive reflector, such as a prism, at the location to be monitored remote from the camera, and by reflecting light emitted by one or more light sources located at the camera, i.e. contained within the camera. have. According to some embodiments, which will be described in greater detail below herein, additional functions requiring power may be provided at the location to be monitored. However, it will be low power and/or configured to be active only for a limited time. Thus, power consumption at the target location to be monitored can all be avoided, or at least significantly reduced compared to systems using beacons or other target objects with active light sources at the target location. This reduces maintenance and facilitates installation, especially for long-term measurements.

The survey reflector advantageously comprises a prism, such as a conventional survey prism. They are generally inexpensive and widely available, providing a cost-effective system. Preferably, a high-precision measuring prism, usually made of glass, can be used. Alternatively, the survey reflector may include a hollow mirror, also referred to as a cat's eye. Other alternatives may also be possible, as will be understood by one of ordinary skill in the art.

The one or more divergent light beams to be reflected by the survey reflector are generated by a camera positioned within a monitoring set-up at a central location, also referred to herein as the camera location, while for example a survey reflector provided within a beacon or target unit. is located at a plurality of different remote locations. Thus, positioning one or more light sources at one central location makes it possible to use significantly higher power levels compared to the case for light sources located at multiple target locations, as explained by the prior art. Providing sufficient power sources, such as batteries and/or power harvesting systems, to a central location is cheaper and/or requires less time and/or effort than providing power to multiple remote locations.

The one or more light sources may be located entirely on one side of the body or, alternatively, may be partially integrated into the body and arranged to emit light on the side of the body not facing the image sensor. That is, the image sensor is positioned toward the first side of the body, and the first beam is emitted in a direction perpendicular to the second side opposite to the body.

The first light source is arranged at a first distance D1 from the optical input system, ie from the center of the camera object. As described herein below with reference to the drawings, the first distance should be selected such that the reflection of the first divergent light beam from the survey reflector enters the camera through the optical input system and reaches the image sensor.

According to a rough definition, the first distance D1 is less than the dimension of the surface area of the survey reflector at which the first beam strikes the survey reflector, for example the diameter in the case of a circular surface area. This approximation, as commonly used for modeling in physics, is based on several assumptions about the monitoring configuration associated with the configuration represented by the mathematically ideal situation. This assumption is, for example, that the first light source is a point light source and is located in the same plane as the body in which the optical input system is located, that the optical input system is infinitely small, and that the survey reflector receives light centered on the first light source. It involves projecting a perfect conical beam in the plane of the holding body. However, for the first approximation, this model gives a good understanding and initial approximation of the first distance.

In a practical situation, a survey reflector will have a diameter in the range of 10 mm to 200 mm, typically 20 mm to 100 mm. The first distance should be less than the diameter of the survey reflector. If surveying prisms with different diameters are used, the first distance must be less than the minimum diameter of the surveying reflector. For target units such as those shown in Figures 11-15, the first distance must be less than the diameter of the individual survey reflectors.

The first light source advantageously comprises a light emitting diode (LED), preferably a high power LED. The light emitted by the first light source may preferably be in the infrared range, although other wavelengths may be possible. The first solid angle may preferably be greater than 45 degrees, more preferably greater than 50 degrees, and most preferably greater than 60 degrees. The number of first light sources and their position on the body may be selected according to the solid angle of the beam emitted thereby, such that the light generated by the first set of light sources substantially covers the field of view of the camera. Thereby, any survey reflectors positioned within the field of view of the camera will be illuminated by the one or more first light sources, without the need for movement of the camera and/or light beam.

The image sensor is configured to receive and detect reflections of the one or more first divergent beams emitted by the one or more first light sources from all survey reflectors positioned within a portion of a field of view of the camera illuminated by the one or more first divergent beams. do. For this purpose, the image sensor may preferably be a two-dimensional sensor.

By simultaneously irradiating a plurality of individually positioned survey reflectors with one or more diverging beams generated by the one or more first light sources, the plurality of survey reflectors may be measured substantially simultaneously. Thereby, the complexity of the system and the time required for measurement can be reduced.

According to some embodiments, the optical input system of the body includes a non-refractive element such as a slit or pinhole that forms the objective of the camera. In another embodiment, the non-refractive objective optical element is another diffractive element, for example a Fresnel zone plate, a photon sieve, an arcuate slit, a mask or a holographic element. ) may be included. The non-refracting element allows the passage of light, including a light beam formed by reflection of the first beam onto the survey reflector, and ambient light into the camera and onto the image sensor. These non-refractive elements and their advantages have been mentioned above herein and are described in detail in WO 2019/143250 A1.

According to an alternative embodiment, the optical input system comprises a lens or a lens system. Preferably, the optical input system comprises a single lens. If this lens is sufficiently thin, i.e. has low refractive power, and is relatively simple and/or well-defined to mount on the body, then the temperature effect introduced by the lens and/or its mounting will be the result of the data recorded by the image sensor. In processing, it may be reduced and/or addressed, for example, by modeling.

The body on which the optical entry system is provided may be substantially planar, or may have any other geometry that permits positioning the optical entry system or camera objective therein.

The processing unit may be located in the camera or in the camera, for example in the interior space of the camera close to the image sensor. Alternatively, the processing unit may be located remotely from the camera.

The position and/or location of the survey reflector is advantageously determined by image processing of the data recorded by the image sensor.

The system may be used to record data substantially continuously and/or at predetermined sampling intervals. The integration time of the signal measured by the image sensor to compensate for the loss in light intensity due to using a diverging light beam instead of a collimated beam and using a non-refractive optical element such as a pinhole instead of a lens for the camera objective. can be increased.

The use of a survey reflector, for example a prism, instead of an active light source at the target location presents a specific problem, the solution to which is presented herein in another embodiment of the invention described below.

Environmental influences, including ambient (diffuse) light entering the camera, can form disturbances or noise in the measurement and/or monitoring of objects.

In an embodiment, the processing unit is further configured to apply the first code to the first diverging beam by modulation of the beam. Thereby, a defined code or pattern is applied or superimposed on the first diverging beam. This first code may be applied in various ways, which may be well known in the field of signal processing. Advantageously, the first code can be provided by amplitude modulation of the first diverging beam, with the result that the amplitude of the beam varies with time in a defined manner. For example, the beam may change in a sinusoidal fashion with a defined frequency and/or phase. By amplitude modulation of the first divergent beam, by sequentially recording the data of the image sensor, and applying filtering techniques during image processing of the recorded data frame, the environmental influence can be suppressed. While this filtering technique reduces the ambient light (reading: constant light) level in the processed image, preferably to a very low level. Modulated light in the processed image is not suppressed.

It should be understood that the modulation of the light beam may be performed in a variety of different ways, including amplitude modulation, modulation of phase and/or frequency, different polarizations, and the like, as will be understood by those skilled in the art. Modulation at different frequencies as described herein should be understood to encompass any suitable means of providing the beams with a different code that makes it possible to distinguish each reflected beam.

Further, the measurement and/or monitoring of the object may be adversely affected by the reflection (which may be diffuse or specular) of the first divergent beam from a surface other than a survey reflector. These reflections may interfere with reflections from the prism, or even appear as false targets.

However, the reflection of light emitted by the first light source from an object other than the survey reflector will not be sufficiently suppressed by the above-mentioned techniques. Accordingly, an object of the present invention may be to reduce the reflective effect of light generated by a camera on an object other than a survey reflector.

According to an embodiment, the device further comprises one or more second light sources, each for emitting a second diverging beam, the one or more second light sources being at a first distance from the optical input system at which the one or more first light sources are located. arranged at a second greater distance D2, the processing unit being configured to apply a second code to the second diverging lightbeam, the second code being different from the first code. The second code may be applied in a similar manner to the first code. Similar to the first diverging beam, the second diverging beam may preferably have a cone shape with a solid angle Ω2 greater than zero.

Thereby, the one or more second divergent light beams can be distinguished from the one or more first divergent light beams. In particular, the reflection of the first divergent light beam detected by the image sensor is distinguishable from the reflection of the second divergent light beam detected by the image sensor. This can advantageously be used as described in more detail elsewhere in this document.

The second distance should be chosen such that the reflection of the second divergent light beam from the survey reflector does not enter the camera through the optical input system. According to the coarse definition, similar to the coarse definition of the first distance, the second distance is less than the dimension of the surface area where the first beam strikes the survey reflector, for example the diameter in the case of a circular surface area. Above in this specification, typical values for the dimensions of the survey reflectors, ie diameters, have been given. The second distance must be greater than this dimension. If a plurality of survey reflectors with different dimensions, ie different diameters, are used, the second distance should be greater than the largest dimension so that reflection of the second diverging light beam is prevented from entering through the optical input system.

Accordingly, the first and second beams may be distinguished from each other during image processing and/or by physical measurements in the system or measurement configuration.

According to one embodiment, the first beam is amplitude modulated with a modulation frequency and the second beam is amplitude modulated with an antiphase of this modulation frequency. Thus, advantageously the camera objective formed by the non-refractive element, for example a pinhole, will only see the first light source reflected from the prism. However, any other object in the field of view will reflect the light from both light sources back to the object. However, in-phase and out-of-phase modulated light added together will appear as a constant light source and will be significantly suppressed in image processing (similar to ambient light).

According to another embodiment, the first light source may emit light of a first wavelength (λ1), and the second light source may emit light of a second wavelength (λ2) different from the first wavelength. The first and second wavelengths are preferably relatively close to each other such that the image sensor has substantially the same sensitivity to both wavelengths. By fitting the survey reflector with a band pass filter that allows the passage of the first wavelength λ 1 but not the passage of the second wavelength λ 2 , only the first light beam will be reflected by the survey reflector. In this embodiment, the at least one second light source is preferably arranged close to the at least one first light source, ie preferably at a first distance rather than the second distance as mentioned above, so that Avoid differences in illumination of the corresponding reflective surfaces. However, this method may provide acceptable results even for a second light source located at a second distance. Also, in this embodiment, the first and second beams are provided with first and second coding, respectively. As mentioned above, by subtracting the images respectively associated with the first and second codes, the reflection generated by the survey reflector in which the influence of ambient light has been filtered can be obtained.

With these different embodiments, the reflection from the survey reflector can be distinguished from the specular reflection from a surface other than the survey reflector, ie the spurious object.

In addition, it may be desirable to measure the distance between the camera and the survey reflector. In particular, it may be desirable to measure the distance in a time efficient manner.

According to an embodiment, the system further comprises one or more third light sources configured to emit a third divergent beam, wherein the one or more third light sources are at a third distance from the optical input system substantially similar to the first distance. arranged, wherein the processing unit is further configured to apply a third code to the third diverging beam, wherein the third code is different from the first code. When used with one or more of the second light sources described above, the third code is also different from the second code. Similar to the first diverging beam, the third diverging beam preferably has a cone shape with a solid angle Ω3 greater than zero. The first and third diverging beams have substantially the same wavelength. From the images generated at the first light source and the third light source respectively, the distance between the image sensor, ie the camera, and the other survey reflector can be measured. The positions of the first and third light sources are known, respectively, such as the distance between the optical input system and the image sensor and the optical properties of the optical input system. Thereby, the distance between the camera and the survey reflector associated with a particular reflection detected at the image sensor may be determined. The one or more first and third light sources are preferably arranged on opposite sides of the optical input system, since it is possible to maximize a baseline between the detected reflections.

Advantageously, the second and third light sources described herein comprise light emitting diodes similar to the first light source. The first, second and third light sources preferably emit light of substantially the same wavelength unless explicitly stated otherwise.

The image sensor provides frames of raw data substantially continuously or at specified sampling intervals. A series of these raw data frames recorded at different sampling times are subjected to various image processing steps, such as filtering, mathematical operations, etc., to produce an image representing, for example, the reflection from a survey reflector of light emitted from the camera. A series of raw data frames includes at least two, but preferably a greater number of such raw data frames, which may be 1000, 10,000, or even greater. As will be understood by one of ordinary skill in the art, one or more additional steps may also be included. While filtering contributions from other light sources, as described herein above, images for one or more first, second or third light sources each having a different coding or modulation may be acquired. Various information may be obtained from images representing reflections of light originating from the first, second and/or third light sources, respectively.

For example, as described herein, an image relating to a second light source, i.e., an image relating to a first light source, i.e., a second light arriving at the image sensor, is subtracted by subtracting the reflected light having a second code detected by the image sensor. It can be subtracted from the reflected light with 1 code. Thereby, information may be obtained that originates from the first divergent light beam reflected by the one or more survey reflectors. This technique has been shown to suppress the reflection of the first divergent beam from reflective surfaces other than the survey reflector, ie from so-called false objects. Using this technique, suppression of more than 10 dB, especially more than 10-50 dB, was achieved.

By combining the image associated with the light of the first coding with the corresponding image associated with the third coding, the distance between the camera and the survey reflector can be determined. Also, from the symmetrical property of the resulting image, a false object can be recognized.

Additional processing steps may be applied to data recorded by the image sensor and/or to images obtained through processing of this data. In particular, for example, when comparing an image with one or more previously acquired images and/or specification data, a correlation technique is applied to thereby detect and/or determine movement of one or more survey reflectors and/or deformation of the object. can

According to embodiments, the processing unit is further configured to apply a command code to the first diverging beam. Thereby, commands or signals providing instructions, information and/or requests may be sent to the survey reflector. By applying this command or signal to the first diverging beam, it will be broadcast simultaneously to all survey reflectors illuminated by the first diverging beam. To this end, the survey reflector may be provided with a receiver for receiving a command, a target processing unit for detecting and processing it, and preferably one or more additional features for performing an action in response to the command, or they may be arranged next to it have. For example, such an object unit may be provided with, or may include, a survey reflector identification unit as described herein below. An example of such a command or signal could be a command that requests the survey reflector to identify itself, for example, by sending an identification signal in response to the command. Alternatively or additionally, other types of information such as telemetry data may be requested from the survey reflector by this technique.

Another task of the present invention may be to be able to distinguish different survey reflectors from one another.

In one embodiment, the system further comprises a survey reflector identification unit, wherein the identification unit is configured to emit an identification signal upon request from the camera, the identification signal being unique to each survey reflector. This survey reflector identification unit is configured to be arranged in the survey reflector.

The survey reflector identification unit advantageously comprises:

- a receiver for receiving the first divergent beam emitted by the camera;

- a microcontroller coupled to said receiver; and

- an identification unit light emitter configured to emit said identification signal when a command is detected by said microcontroller. The identification signal may advantageously be emitted in the form of a code that is emitted for a limited amount of time.

The receiver may advantageously be an ultra-low power, high-sensitivity receiver with only low power consumption. An example of such a receiver is described in WO 2020/027660 A1. The light receiver may be configured to receive the first light beam substantially continuously, and the microcontroller determines whether a command or request for an identification signal is provided to the first light beam.

The camera may advantageously be configured to emit a command or request for an identification signal via the light emitted by the first light source, for example as a signal or code superimposed or added to the first divergent light beam. Thereby, the request for identification is simultaneously transmitted to all survey reflectors within the portion of the field of view covered by the one or more first divergent light beams. That is, the same identification request is received by each survey reflector, and in response each emits its own unique identification signal back to the camera.

This enables substantially simultaneous identification of each survey reflector within a portion of the field of view of the camera illuminated by the one or more first light sources in a substantially automated manner, thereby allowing automatic surveying and/or monitoring of a plurality of survey reflectors make it easier

Since the identification unit light emitter, which may for example comprise a light emitting diode, only emits an identification signal in response to a request, the energy consumption of the identification unit can be kept low.

The different embodiments described above may be combined in a manner understood by a person skilled in the art.

In a second aspect of the present invention, there is provided a method for monitoring a plurality of survey reflectors on an object, the method comprising:

at the first camera position,

emitting, by each of one or more first light sources, a first divergent beam having a solid angle greater than zero toward the plurality of survey reflectors, wherein the plurality of survey reflectors comprises the one or more first light sources from the one or more first light sources. irradiated substantially simultaneously by the diverging beam, wherein the at least one first light source is maintained in a substantially fixed position; and

recording, by an image sensor, data representative of a reflected light beam comprising reflection of the first divergent beam by the plurality of survey reflectors;

monitoring the locations by and

determine a position of each survey reflector from the data by image processing of the data, and survey at least one of the plurality of survey reflectors based on a comparison of the determined position of each survey reflector with a previously determined position of the survey reflector detecting movement of the reflector.

includes

The method according to the second aspect of the invention can advantageously be carried out using the system according to the first aspect to achieve corresponding effects and advantages.

In a preferred embodiment, the image processing of the data comprises one or more steps described in relation to the first aspect.

In particular, the method may be further configured to reduce environmental interference and/or disturbance from a false object, as described above with reference to the first aspect.

In one embodiment, a first code is applied to the first diverging beam. This can be applied according to any method as described with reference to the first aspect. Filtering techniques may be applied when image processing the data, thereby distinguishing light originating from reflections of the first beam from other light sources and/or other reflections.

According to some embodiments, the method further comprises the following steps:

providing a body provided with an optical input system allowing passage of light, the body having a first side and a second side, the first side facing the interior space of the camera and the second side facing away from the interior space arranging the body toward, such that the image sensor is arranged in the interior space on a first side of the body and the one or more first light sources are arranged on the second side of the body;

arranging the one or more first light sources at a first distance (D1) from the optical input system;

arranging one or more second light sources at a second distance (D2) greater than the first distance (D), emitting a second divergent beam by each of the one or more second light sources; and

applying a second code to the second diverging beam, wherein the second code is different from the first code.

The first and second distances are preferably defined as defined above herein with reference to the first aspect. The first and second codes may be applied according to one or more of the techniques described above with reference to the first aspect.

According to some embodiments, the method further comprises:

generating a first image from the reflected light provided with the first code;

generating a second image from the reflected light provided with the second code; and

subtracting the second image from the first image and determining a position and/or movement of one or more of the survey reflectors from the resulting image.

Thereby, the image due to the reflection of the first beam, ie the measuring beam, can be separated from disturbances caused by environmental influences.

Another task of the present invention is to distinguish the reflection from the survey reflector from other specular reflections, i.e. false objects.

According to an embodiment, the method further comprises providing one or more third light sources and applying a third code to the third diverging beam, wherein the third code is different from the first code. The third light source is arranged at a third distance D3 comparable to the first distance from the optical input system. The process of applying the coding may be performed as described above. The method further includes determining whether the detected image originates from a survey reflector or from another reflective element, based on images obtained for reflections of the first and third diverging beams, respectively. This may depend on whether the detected image is mirrored with respect to the position of the light source.

The reflections from the survey reflectors of each of the first and second lightbeams will appear as two separate distinguishable objects in the image obtained by image processing of the data. If reflected from a prism or reflected from a hollow mirror when the light source is positioned outside the focal length of the hollow mirror, the image will appear mirrored about the center of the prism or hollow mirror. Thereby it can be confirmed that these reflections originate from the survey reflector and not from other reflective surfaces within the camera field of view.

Another task of the present invention may be to determine the distance between the camera and the survey reflector.

This may be realized by an embodiment wherein the method further comprises the step of providing one or more third light sources as described herein above, preferably on the opposite side of the non-refracting element than the first light source. . The distance between the camera and the survey reflector is the first point p1 in the resulting image resulting from the reflection from the survey reflector of the light emitted from the first light source and the reflection from the survey reflector of the light emitted from the third light source may be determined from the distance between the second points p2.

In this embodiment, the distance between the camera and the survey reflector can be determined because of the positions of the first and third light sources relative to each other and to the optical input system, for example a non-refractive element such as a pinhole. The first and third light sources need not be located on opposite sides of the non-refractive element, but this may be desirable as it maximizes the baseline between the two light sources while both light sources remain within a set maximum distance from the optical input system. have.

Embodiments for measuring distance may advantageously be combined with any of the embodiments described above to suppress unwanted reflections. Thereby, the distance between the camera and the survey reflector can be measured while the reflection is discriminated and/or suppressed.

According to an embodiment, the distance may be determined by a method further comprising:

- providing the body with first and second optical input systems;

- determining the distance between the camera and the survey reflector from the baseline between the first and second optical input systems and the distance between the projected object images generated from the first and second optical input systems.

The first and second optical input systems may comprise one or more lenses, preferably a single lens, or a non-refractive element, for example a pinhole, which acts as the objective of the camera, as described herein above.

According to another embodiment, the distance may be determined using two cameras positioned at different camera positions, the cameras arranged such that the optical axis of each camera is tilted relative to each other to see the same set of survey reflectors. Way,

monitoring the positions at a second camera position positioned away from the first camera position, wherein a first viewing line between the first camera position and a reference survey reflector is between the second camera position and the reference oriented obliquely with respect to a second line of sight between the survey reflectors; and

determining three-dimensional coordinates of the survey reflector based on the monitoring at the first camera position and the second camera position;

further comprising,

The monitoring at the second camera position is performed similarly to the monitoring at the first camera position.

The three-dimensional coordinates may be determined according to various methods, as will be understood by one of ordinary skill in the art. For example, a triangulation method may be used. Generally, in the above configuration, one or more parameters are known, such as the distance between one or more features and/or the orientation angle of the one or more features with respect to each other.

Determination of the three-dimensional coordinates of the survey reflector is determined by determining the least amount of the survey reflector being monitored by both cameras and at least one known distance (between two survey reflectors, between two cameras, or between one of the cameras and one of the survey reflectors). may need This will provide a set of equations with a number of unknowns that can be solved by known mathematical methods. Optionally, furthermore, the orientation or tilt (pitch and roll) of the camera can be measured, for example by means of a tilt sensor provided in the camera. Knowing the tilt of the camera reduces the number of survey reflectors needed to solve the equation.

As described above with reference to the first aspect, another challenge of the present invention may be to distinguish different survey reflectors.

According to one embodiment, the method further comprises:

emitting a survey reflector identification command using the one or more first light sources; and

emitting, by an identification unit light emitter located in the survey reflector, an identification signal in response to the survey reflector identification command.

Advantageously, the identification signal is emitted in the form of a code that is emitted for a limited time. Preferably, the identification signal is unique for each survey reflector, in particular for a neighboring survey reflector. In the case of survey reflectors positioned far enough apart to be distinguishable from each other based on distance, the identification signal or code can be reused. In this case, it may be combined with an additional code or signal that, when detected and/or interpreted together with the identification signal, provides a unique identification.

This can be accomplished by using a survey reflector identification unit as described above.

According to a third aspect, there is provided a system for monitoring a survey reflector arranged at a plurality of locations on an object, the system comprising:

A camera configured to monitor the survey reflector, comprising:

one or more first light sources, each for emitting a first divergent beam;

one or more second light sources, each for emitting a second diverging beam;

an image sensor for receiving a reflected light beam comprising reflection of the first divergent beam by the plurality of survey reflectors and providing data; and

a body provided with an optical input system, the body having a first side facing an interior space of the camera and a second side facing away from the interior space, wherein the image sensor is located within the interior space, the first and first 2 a light source is located on the second side of the body -

a camera comprising; and

a processing unit configured to process the data

including,

the first light source is arranged at a first distance D1 from the optical input system, the second light source is arranged at a second distance D2 greater than the first distance from the optical input system,

The processing unit is configured to apply the first code to the first beam and to apply the second code to the second beam, wherein the second code is different from the first code.

The features of the system according to the third aspect are preferably similar or similar to the corresponding features of the system according to the first aspect, and can be combined with any one of its features or embodiments.

The first and second diverging beams are divergent beams having a solid angle greater than zero, and may preferably have a cone shape.

In particular, the processing unit advantageously operates and/or functions in the manner described above with reference to the first aspect.

According to a fourth aspect, there is provided a method for monitoring positions on an object, the method comprising:

providing a plurality of survey reflectors on the object, each survey reflector being provided at one of the locations;

the locations,

emitting, by each of one or more first light sources, a first divergent beam towards the plurality of survey reflectors;

emitting, by each of one or more second light sources, a second divergent beam towards the plurality of survey reflectors; and

recording, by an image sensor, data representative of a reflected light beam comprising reflection of the first divergent beam by the plurality of survey reflectors;

monitoring by; and

determine a position of each survey reflector from the data by image processing of the data, and survey at least one of the plurality of survey reflectors based on a comparison of the determined position of each survey reflector with a previously determined position of the survey reflector detecting movement of the reflector.

including,

The method further comprises applying a first code to the first diverging beam and applying a second code to the second diverging beam, wherein the second code is different from the first code.

These features make it possible, in particular, to distinguish the reflection of a survey reflector from other reflections and/or ambient light entering the camera and/or to reduce influences and/or disturbances from environmental influences and/or reflections from surfaces other than the survey reflector. make it possible to reduce

The method according to the fourth aspect may be advantageously performed using the apparatus according to the third aspect to obtain the technical effects and/or advantages as described above with reference to the third aspect.

A method according to the fourth aspect may comprise one or more steps or features described with reference to the second aspect.

According to a fifth aspect of the present invention, there is provided a beacon comprising a survey reflector as described above. The beacon may also include a survey reflector identification unit as described above. Furthermore, the survey reflector in the beacon may be provided, ie fitted, with an optical band pass filter and/or an active modulator as described above.

According to a sixth aspect, there is provided a system for monitoring positions on an object comprising a system according to the first or third aspect and a plurality of beacons according to the fifth aspect.

As described above, in contrast to conventional surveying systems that use a collimated laser beam, a broad divergent beam from the LED is preferably used. The use of a diverging light beam leads to a lower luminous flux or light intensity per cross-sectional area in the survey reflector. As a result, the intensity of the reflected light reaching the camera and image sensor will be lower. This can place undesirable limits on the operating range of the system. In particular, in preferred embodiments where the camera is provided with a pinhole or other non-refractive optical element as the objective, this can lead to very low light intensity in the image sensor. Therefore, it would be desirable to increase the luminosity of the reflected light reaching the image sensor.

According to a seventh aspect, there is provided a subject unit for use in any of the systems or methods described above, the subject unit comprising a plurality of survey reflectors arranged in one single plane.

By use of a target unit comprising a plurality of survey reflectors arranged in one single plane, the amount of reflected light is increased, compared to a situation in which individual survey reflectors are used for each of a plurality of positions in the object to be monitored, so that the image sensor leads to higher light intensity. Thereby, the working distance and detection range of a survey system, such as the survey system described above herein, may be increased. A target unit comprising a plurality of survey reflectors, such as survey prisms, can be viewed from a greater distance than the individual survey reflectors typically used.

The survey reflector is preferably a high-precision survey reflector, for example a survey half-timer of the type made of glass. It is a high-precision machined glass prism, which has significantly higher reflected light accuracy and intensity than inexpensive molded plastic prisms commonly used in the field of surveying.

The survey reflector is arranged in one single plane in that the corresponding points or positions of the plurality of survey reflectors are all arranged in the same plane. This effectively achieves a substantially planar survey reflector having a larger reflection area than a single survey reflector.

It can be seen that multiple surveying reflectors are needed to increase the intensity of the reflected light, since increasing the dimensions of a single survey reflector or prism will not lead to increased intensity.

As mentioned above, the minimum size of an individual survey reflector is considered to be determined by the distance between the first light source, typically an LED, and the pinhole or other non-refractive optical element used as the camera objective. According to theory, when using a prism or survey reflector with a circular base facing the incoming light beam, its diameter should be at least equal to this distance. When using a prism with a triangular or hexagonal base, it must be dimensioned such that the diameter of the hypothetical inscribed circle is at least this distance.

According to one embodiment, the survey reflectors are arranged in an array, one of the survey reflectors is arranged at the center of the array, the center representing a point of symmetry of the array. As mentioned an array located in one single plane may have mirror symmetry and/or rotational symmetry with respect to the central reflector. For example, the survey reflectors may be arranged in a hexagonal array pattern. In this way, the survey reflectors are arranged in an efficient arrangement. That is, the survey reflector is densely packed to maximize the reflective area of the target unit. With the symmetrical arrangement of the survey reflectors, the increase in intensity or power of light reflected by multiple survey reflectors as compared to a single survey reflector will be substantially the same in both the vertical and horizontal directions.

According to one embodiment, each survey reflector has a surface configured to receive an incoming light beam, said surface being substantially circular. Alternatively, other shapes of the light receiving surface or base of the reflector may be used, such as triangular or hexagonal.

The hexagonal arrangement provides an efficient arrangement of the reflectors, especially when a survey reflector, which is typically a prism, has a circular base or front surface that receives an incoming light beam. Also, in the case of a base or other shape of the front face that receives the incoming light beam, for example a triangle, a hexagonal arrangement may provide the most efficient packing. Alternatively, when using a survey prism with a triangular base, the reflectors may be arranged such that the triangular sides are adjacent to each other.

According to an embodiment, the plurality of surveying reflectors is realized by a plurality of surveying prisms, the prisms being preferably substantially identical, and the surfaces of the prisms configured to receive the incoming light beam are arranged in said one single plane.

According to another embodiment, the plurality of survey reflectors is realized by a plurality of hollow mirrors each having a center point, the hollow mirrors preferably being substantially identical, the center points of all mirrors being arranged in said one single plane.

According to one embodiment, the plurality of survey reflectors comprises from 13 to 35 reflectors. The number of survey reflectors in the object unit is typically selected to achieve efficient reflection of the light beam emitted by the camera and/or survey system, and maintains the reflective area of the object unit to be considered substantially dotted with respect to the camera. The number of individual survey reflectors included in the target unit may be set according to the distance between the camera and the target unit. Increasing the number of survey reflectors in a target unit will generally increase the working distance or detection range of the system.

Features of different embodiments of the subject unit may be combined.

According to an eighth aspect, a system according to the first and/or third aspects described hereinabove further comprises a plurality of target units according to the seventh aspect.

In summary, according to advantageous embodiments, there is provided a system according to the first and third aspects, wherein the camera uses a pinhole or other non-refractive optical element as an object, wherein a plurality of target units according to the seventh aspect are objects to be monitored are arranged in As described above, the survey light to be reflected by the survey reflector of the target unit is generated at the camera as one or more divergent light beams, the one or more divergent light beams comprising at least 10%, preferably 50% or more of the camera's field of view as divergent light beams. Forms a divergent light beam having a solid angle to be illuminated by (s). With this system, the point or position of an object such as a building or other structure can be monitored with high angular precision, while the system avoids the use of any moving parts.

Although the use of a wide beam such as a divergent beam emitted by an LED in combination with the use of a pinhole instead of a lens as a camera objective can lead to loss of light compared to conventional systems using a camera with a collimated laser beam and a lens-based objective, , a reliable system providing measurements with high accuracy has been achieved. As discussed above herein, the loss of light may be compensated for by using a high power LED light source, integrating measurements and/or using multiple survey reflectors at individual locations on the object to be monitored.

Embodiments of the present disclosure will be described below herein with reference to the accompanying drawings. However, the embodiments of the present disclosure are not limited to specific embodiments, and should be construed to include all modifications, changes, equivalent apparatus and methods and/or alternative embodiments of the present disclosure.
As used herein, the terms “have”, “may have”, “include” and “may include” refer to the corresponding feature (eg, elements such as numbers, functions, operations or parts), and does not exclude the existence of additional functions.
“A or B (A or B)”, “at least one of A or/and B”, or “at least one of A or/and B ( Terms such as "one or more of A or/and B)" include all possible combinations of the items listed with them. For example, "A or B", "at least one of A and B" or "at least one of A or B" means (1) comprising at least one A, (2) comprising at least one B or (3) comprising both at least one A and at least one B.
Terms such as "first", "second" as used herein can modify various elements, regardless of the order and/or importance of the corresponding elements, and define the corresponding elements. This term may be used to distinguish one element from another. For example, without departing from the scope of the present invention, a first element may be termed a second element, and similarly a second element It may also be called the first element.
An element (eg, a first element) is "coupled with/to" or "(operatively or communicatively)" to/from another element (eg, a second element) When "connected to", an element may be directly coupled to/from another element, and there may be an intervening element (eg, a third element) between the element and the other element. Conversely, when an element (eg, a first element) is "directly coupled with/to" or "directly connected to" another element (eg, a second element). , there are no intervening elements (eg, third elements) between the element and other elements.
The expression "configured to (or set to)" as used herein means "suitable for", "having the ability to Interchangeable with "having the capacity to", "designed to", "adapted to", "made to" or "capable of" can be used negatively. The term "consisting of (or set to)" does not necessarily mean "specifically designed to" at the hardware level. Instead, the expression “apparatus configured to...” may mean that the device is “capable of” with another device or part in a particular context.
The terminology used to describe various embodiments of the present disclosure is for the purpose of describing particular embodiments, and is not intended to limit the present disclosure. As used herein, the singular form is intended to include the plural form as well, unless the context clearly dictates otherwise. All terms used herein, including technical or scientific terms, have the same meaning as commonly understood by one of ordinary skill in the relevant art unless otherwise defined. Commonly used terms defined in the dictionary should be interpreted with the same or similar meaning as the contextual meaning of the related art, and should not be construed in an ideal or exaggerated meaning unless clearly defined herein. . In some cases, even terms defined in the present disclosure should not be construed as excluding embodiments of the present disclosure.
In determining the scope of protection conferred by the claims of this document, any element equivalent to the elements specified in the claims should be properly considered.
BRIEF DESCRIPTION OF THE DRAWINGS The invention will be discussed in more detail below with reference to the accompanying drawings:
1a to 1c show several schematic configurations of a system for monitoring the position and/or movement of an object;
2 schematically shows a system according to a general embodiment of the present invention;
3 schematically shows a system according to another embodiment of the present invention;
4 schematically shows a configuration for reducing environmental interference;
Fig. 5a schematically shows a configuration for distinguishing reflection from a survey reflector from other reflective elements;
Figures 5b-5e schematically illustrate the principle of figure 5a;
6 schematically shows a schematic measurement configuration according to an embodiment;
7 schematically shows an arrangement enabling identification of a survey reflector according to an embodiment;
8 shows a functional overview of a camera that can be used in the present invention;
9 shows an exemplary housing for a camera according to the present invention; and
10 shows a flowchart of an example of system functionality;
11 shows a target unit according to an embodiment of the present invention;
12a to 12d schematically show cross-sections of the target unit of FIG. 11 according to different embodiments;
13A-13D show an arrangement of a survey reflector in a target unit according to an embodiment of the present invention;
14A-14C show an arrangement of a survey reflector in a target unit according to an embodiment of the present invention;
Figure 15 provides a rear view of the arrangement of Figure 14a.

In general, the present invention relates to surveying an object or tracking the movement of an object by tracking one or more survey reflectors attached to the object. More particularly, the present invention relates to an apparatus comprising a camera provided with one or more light sources configured to emit a diverging light beam for surveying and/or tracking positions on an object.

Although the illustrated embodiments are described using an optical input system, i.e., a camera having a camera objective formed by a non-refractive element in the form of a pinhole in the camera objective, alternatively the non-refractive element may be used in any of the ratios mentioned above herein. It should be understood that it may be a refractive element. Alternatively, the optical input system may be formed by a lens system, such as a lens system comprising a single lens. Similarly, although embodiments have been described using a prism as a survey reflector, it should be understood that other reflective elements may also be used, such as other types of prisms or hollow mirrors.

1a shows a possible configuration of a system in which an object 3 is monitored. The system comprises a sensor device such as a camera 7 . The system also comprises a plurality of survey reflectors 1 which are attached to the object 3 at a plurality of positions. The object 3 is shown comprising one or more buildings to which the survey reflector 1 is fixed. However, object 3 may alternatively be any other structure such as a tower, tunnel (FIG. 1B) or bridge (FIG. 1C), but may be a vehicle (such as a boat on land) or a natural object such as a large rock. may be

The object 3 is monitored by monitoring or measuring the position of the survey reflector 1 . By monitoring its position over time, the movement of all or part of the object 3 can be detected. Also, preferably, the amount, extent and/or direction of movement can be determined. Thereby, state or mechanical properties such as stability or integrity of the object 3 can be monitored.

One camera 7 is shown. However, the system may include more than one camera 7 .

According to the invention, the camera 7 is arranged to generate a divergent light beam 5 , also referred to as a first beam, and transmit it to a plurality of survey reflectors 1 . The survey reflector 1 reflects the portion of the divergent light beam 5 impinging on it, thereby forming a reflected beam 6 which is reflected back to the camera 7 . As will be described in more detail herein below, the generally substantially cone-shaped light beam 5 has a solid angle Ω1 covering the field of view of the camera 7 . Thereby, a plurality of survey reflectors 1 can be monitored substantially simultaneously.

1b shows an implementation in a tunnel 3 . A railroad with railroad sleepers 12 passes through a tunnel 3 . Both the tunnel wall and the railroad sleepers 12 are provided with a survey reflector 1 . The camera 7 is arranged so that it can see all the survey reflectors 1 within its field of view.

1c shows an embodiment for a leg 3 . The legs 3 are provided with a plurality of surveying reflectors 1 . The camera 7 is arranged so as to be able to see all the survey reflectors 1 .

The survey reflector 1 shown in FIGS. 1A-1C can be realized by a single high-precision survey reflector such as a survey prism. Alternatively, advantageously a plurality of survey reflectors realized by the object units 1100 , 1101 , 1102 , 1103 described hereinbelow with reference to FIGS. 11 and 12a to 12d may be provided at each location. have.

2 provides a schematic diagram of the measurement principle of a system 20 for monitoring a plurality of positions on an object 3 according to the first aspect of the invention. For ease of illustration and understanding of the optical principle, FIG. 2 shows a system 20 monitoring one survey reflector 21 . However, as shown in FIGS. 1A-1C , the system 20 , particularly its camera 27 , may be used to monitor a plurality of such survey reflectors. Although the survey reflector 21 is formed by a prism in the illustrated embodiment, other types of reflectors, such as hollow mirrors, may also be used. Also alternatively, a target unit as shown in FIGS. 11 to 15 comprising a plurality of such reflectors may be used instead of a single reflector 21 .

The system 20 includes a camera 27 and a processing unit 29 that may be included or arranged within the camera 27 . Alternatively, it may be arranged remotely from the camera 27 .

The camera 27 comprises a first light source 22 , which emits a diverging beam 25 , also referred to as a first diverging beam. The first light source 22 generally comprises a light emitting diode (LED). The first beam 25 preferably has a first solid angle Ω1 large enough to cover substantially the entire field of view of the camera 27 . Alternatively, as described above, a plurality of first light sources 22 may be provided to substantially cover the field of view of the camera. In such an embodiment, the solid angle of each beam does not necessarily cover the field of view, as long as the assembly of beams substantially covers the field of view. Thereby, all survey reflectors 21 located within the field of view of the camera, i.e. seen by the camera, are irradiated with the first light beam 25 without moving, rotating or scanning the camera or the light beam (one or more survey reflectors are shown in FIG. 1A ). There is a possible exception to being shadowed by obstacles such as pedestrians or vehicles when monitoring a building as shown, or trains when monitoring a tunnel as shown in FIG. 1B). Where a plurality of first light sources 22 are provided, all of the survey reflectors will be illuminated by a beam from at least one of the light sources.

In some embodiments, the first divergent beam 25 or the accumulation of the first divergent beams emitted by the plurality of first light sources 22 only partially covers the field of view of the camera. For many surveying applications, this may be sufficient. The partial coverage may be, for example, at least 10% or more, or in some embodiments at least 50%, depending on the application.

The first beam 25 is preferably amplitude modulated, thereby exhibiting a defined change in time in its amplitude. Alternatively and/or additionally, other types of coding may be applied to the first beam herein, as described in more detail in the Invention section above. As described above, by applying appropriate filtering techniques during image processing of the data, environmental impacts on the measurement, such as interference by ambient light, can be reduced.

The survey reflector 21 will reflect a portion of the receiving first beam 25 to form a reflected beam 26 that is reflected back towards the camera 27 .

The device 20 further comprises an image sensor 24 arranged to receive reflected light, ie a portion 261 of the reflected beam 26 entering the camera 27 . As a result of receiving the reflected light 261 , the image sensor 24 generates data in the form of a two-dimensional image in a preferred embodiment.

Between the image sensor 24 and the first light source 22 or at least the emitting surface thereof, a substantially planar body 28 in the illustrated embodiment is arranged. The body 28 is opaque and includes an optical input system forming the object of the camera in the form of a non-refractive element, such as a pinhole 23 in the illustrated embodiment. In the illustrated embodiment, the body 28 forms part of the camera housing.

Although the description herein will focus on optical input systems formed by pinholes, other types of non-refractive elements, particularly as described in WO 2019/143250 A1, are equally suitable as refractive elements such as single thin lenses. can do.

The processing unit 29 determines the position of each survey reflector from the data, generally by image processing of the data provided by the image sensor, and compares the determined position of each survey reflector with its previously determined position. and detect movement of one or more of the plurality of survey reflectors based on the survey reflectors.

By simultaneously irradiating all survey reflectors positioned within the field of view of the camera with divergent beams generated by the one or more first light sources, all survey reflectors measure substantially simultaneously, without the need to move the camera and/or scan the first beam. can be Thereby, the complexity of the system and the time required for measurement can be reduced. The survey reflector is a passive reflective element and therefore does not require any power source.

The first light source 22 is arranged at a first distance D1 from the pinhole 22 . Approximately, the first distance D1 is less than a diameter equal to the diameter D of the aperture or surface area of the survey reflector 21 on which the first beam 26 is incident. If the light source is positioned outside this radius, the viewer, ie the pinhole 23, will not be able to 'see' the reflection of the first light source according to optical principles. Light source 22 can preferably be assumed approximately as a point light source. A perfect survey prism will reflect the divergent light beam emitted from the first light source (if the beam width is wide enough to cover the entire aperture of the prism) back to the (point) light source. The apparent distance of the reflective light source to an observer positioned at the same location as the light source is twice the distance from the light source to the prism. The beam width or solid angle (in degrees or steradian) of the reflected beam is limited by the aperture of the prism and the distance between the light source and the prism. The diameter of the reflected beam spot at the location of the light source is twice the diameter of the aperture of the prism (because the virtual light source 22v is at twice the distance from the light source to the prism). The center of the spot of the virtual light source 22v is located at the same position as the point light source 22 . Thus, an observer (or receiver) at the same distance from the prism as the light source will only be able to 'see' the reflective light source if it (or the receiver) is located within a radius of the diameter of the prism from the light source. In other words, the reflection 251 of the first beam 25 at the prism 21 will appear at the pinhole 23 only if the first light source 22 is located within a distance from the pinhole not greater than the diameter of the prism. This principle will be used in other embodiments to differentiate and/or reduce the effect of ambient light and/or the reflection of the first beam from a surface other than a survey reflector, as described in more detail below.

3 schematically shows a system 30 according to another embodiment. The system 30 is similar to the device 20 shown in FIG. 2 , but the camera 37 is provided with an additional light source in addition to the first light source 321 , also referred to as a second light source 322 . The second light source 322 is similar to the first light source and is disposed at a second distance D2 greater than the first distance D1 from the pinhole 33 . Similar to the rough definition of the first distance D1 , the second distance D2 is greater than the diameter D of the prism 31 . The first and second light sources 321 , 322 may be located on opposite sides of the pinhole 33 , but this is not required. Similar to the first light source 321 , the second light source 322 also preferably emits a diverging light beam in the form of a second beam 352 having a second solid angle Ω2 large enough to cover the camera's field of view. emit Also, similar to the embodiment of FIG. 2 , a plurality of first and second light sources 321 and 322 may be provided. According to the theory summarized above with reference to FIG. 2 , this is the reflection of the first light source 361 , whereas the reflection 362 of the second light source 322 by the prism 31 does not enter through the pinhole 33 . will enter through the pinhole 33 (as described above with reference to FIG. 2 ). As can be seen, the virtual light source 322v corresponding to the second light source 322 will not be visible in the pinhole 33 . Thereby, according to an embodiment of the present invention, this configuration facilitates suppression of reflections from false objects.

Also, elements or surfaces other than the survey reflector 31 positioned within the field of view of the pinhole 33 and irradiated by the first beam 321 may reflect light diffusely or as a specular surface. Such reflections may interfere with reflections from the prism 31 or even create false objects. In order to obtain reliable measurement results, ie reliable and adequate monitoring of the object to be monitored, it is desirable to be able to distinguish between these unwanted reflections and the reflection of the first beam from the prism.

This is achieved, for example, by applying a first code to the first beam by amplitude modulating the first light beam 351 emitted from the first light source 321 with a specified modulation frequency, and applying a second code to the second beam. can be As explained above, only the reflection of the first light source 321 from the prism and not the second light source 322 will reach the pinhole. Other elements in the field of view will reflect light from both light sources back into the pinhole.

By providing different codes, Code 1 and Code 2, respectively, to the light emitted by the first and second light sources 321 and 322, the signals from the first and second light sources, respectively, are transmitted during processing of data from the image sensor. can be separated. This has been described in more detail in the [Content of the Invention] section above herein.

By subtracting the two images obtained after filtering for each of the first and second codes, the reflection generated by the prism 31 can be obtained. From the image generated from the subtraction, the position and/or movement of the prism 31 can be determined.

Alternatively, an optical band pass filter may be provided in the prism 31 , ie in front of the prism 31 , allowing passage of light of one wavelength and not allowing passage of light of another wavelength. A first light beam having a first wavelength and provided with a first code will be reflected by the prism but a second light beam having a second wavelength and provided with a second code will not be reflected. Thereby, the prism will only reflect light from the first light source 321 , while other elements within the camera's field of view will reflect both light from the first light source 321 and the second light source 322 . This method will also work if the second light source is located at a distance from the pinhole 33 less than the diameter of the prism.

In another embodiment illustrated in FIG. 4 , the effect of environmental interference on the measurement of the survey reflector is a constant light, i.e. liquid crystal for example modulating the amplitude of the reflected light 46 for a specific frequency that can be distinguished from ambient light. This can be reduced by fitting an active modulator 412, which is a modulator, to a survey reflector. Also, for this embodiment, one light source 42 is sufficient. The light beam 45 emitted thereby need not be modulated, but may still be.

In the embodiment shown in FIG. 5A , the camera 57 includes a first light source 521 and an additional light source, also referred to herein as a third light source 522 . Both light sources are located within a distance d from the pinhole 53 . Using the rough definition described above, the distance d does not exceed the diameter D of the survey reflector 51 . Accordingly, portions of the reflected beams 561 , 562 of both the first light beam 521 and the additional light beam 522 respectively reflected by the survey reflector 51 will enter the pinhole 53 . Because of their different codes, each projection on the image sensor 54 can be distinguished using image processing. The light sources 521 , 522 may advantageously be located on opposite sides of the pinhole 53 , although this is not required. The camera 57 may further be provided with one or more second light sources positioned further from the pinhole as described with reference to FIG. 3 , although details of such combinations are omitted herein.

5B-5E, this configuration captures reflection from a prism 51 or hollow mirror forming a survey reflector and reflection from another mirror-like surface, also called a false object, located within the field of view of the camera 57. make it possible to distinguish To this end, the first beam 521 is provided with a first code, and the beam 522 is provided with another codeE. From the properties of the image due to the reflection of the two light sources, in particular the presence or absence of mirror symmetry, whether the reflection originates from a prism or from another mirror-like surface can be distinguished.

When reflected from the prism 51 as shown in Figure 5b, the first light source 521, for example an LED, to the right of the pinhole will create a virtual light source 521v that appears to the left, and the pinhole 53. Light source 522, which may be an additional LED to the left of , will create a virtual light source 522v to the right. In other words, and more generally, the images of the two light sources are mirrored about the center of the prism.

However, this is not the case when it is reflected from a flat mirror 5101 as shown in FIG. 5C or from a spherical mirror, ie, a convex mirror 5102, as shown in FIG. 5D. In these cases, the image will not be mirrored.

In the case of a hollow mirror surface, ie, a concave mirror surface 5103, as shown in FIG. 5E, the image will be mirrored only if the two light sources are located outside the focal length of the mirror.

Also, from the distance between two images or objects recorded by the image sensor 54 in the embodiment shown in FIG. 5A , the distance D _T between the camera and the survey reflector can be determined. The distance between the images i1 , i2 recorded on the image sensor 54 is the known distance between the two light sources, the focal length D _f of the camera (ie the distance between the image sensor and the pinhole also known), the present The absolute (two-dimensional) angle of the image sensor to the object, which may be measured according to other principles described in the specification and/or known to those skilled in the art, and the distance between the pinhole and the prism (D _T ) which may be determined accordingly depend on

Another measurement configuration that makes it possible to determine the distance between the camera and another survey reflector is shown in FIG. 6 . In this configuration, two cameras 67A, 67B are used, located at different camera positions but looking at the same scene, ie, the same set of survey reflectors 61 . These cameras 67A, 67B may be any of the cameras described above, and thus are operated according to any one of the methods described above. The camera is arranged such that the respective optical axes are arranged at a preferably known angle α with respect to each other. By means of triangulation measurements, the distance from the camera to the survey reflector 61 can be determined in a manner understood by a person skilled in the art. Moreover, the three-dimensional coordinates of the survey reflector 61 can be determined, as described in the [Invention] section of this document.

Moreover, in each of the embodiments described above, each survey reflector prior to starting a measurement or monitoring session and/or while monitoring a set of survey reflectors over time, in order to distinguish reflections from different survey reflectors from each other. It may be desirable to identify This may be made possible by an embodiment as shown in FIG. 7 . It should be noted that the embodiment of FIG. 7 may be applied to or incorporated into each of the embodiments described above herein.

As shown in FIG. 7 , the survey reflector 71 includes a light receiver 71 for receiving a part of the first beam 75 emitted by the light source 72 of the camera 77 , and a light receiver upon receiving light. A microcontroller 719 forming part of or coupled to the light receiver 714 is provided and/or fitted or coupled to detect and/or process the signal generated by the . Also, an identification unit light emitter 712 , eg an LED, is provided in the survey reflector and coupled to the microcontroller 719 . The light receiver 714 , the microcontroller 719 and the light emitter 712 may form a survey reflector identification unit 716 . The processing unit 79 associated with the camera 77 is configured to control the first light source 72 so that a signal can be imposed on the first light beam 75 . This signal may include an identification request. When this request signal is received by the light receiver 714 , the identification unit light emitter 712 emits an identification signal, for example in the form of a code that is emitted only for a short time. When this identification signal, which is unique for each survey reflector, is received by the image sensor 74 of the camera 77 , the survey reflector can be identified.

A survey reflector 71 and a survey reflector identification unit 716 may be arranged in a survey reflector unit 718 , which may also be referred to as a beacon.

The object 3 may be provided with a plurality of survey reflector units 718 at these positions for monitoring its different positions. In the illustrated embodiment, the survey reflector 71 is provided by a prism. However, it will be appreciated that other types of reflectors, for example hollow mirrors, also referred to as cat's eyes, may be equally suitable.

By configuring the processing unit 39 to cause the camera 77 , in particular its light source, to send an identification request to all survey reflector units within its reach, each of which is an identification unit of a respective survey reflector unit 718 . can be uniquely identified by the identification signal transmitted by 716 .

A component according to an embodiment of the camera 7 will now be described in more detail in particular with regard to its functional aspects. This description applies similarly to all cameras 27, 37, 47, 57, 67A, 67B, 77 described in the other embodiments above herein.

8 shows an example of a camera 7 . Exemplary camera 7 includes non-refractive optics 101 , image sensor 120 , clock 123 , memory 15 , one or more position and/or orientation measurement components 16 , output unit 17 , It has a processing unit 9 connected to an input unit (or user interface) 19 , an electronic networking module(s) 109 and one or more light sources 102 . The non-refractive optics 101 is shown coupled to an image sensor 120 . This latter "connection" need not be a physical connection. Here, “connection” is intended to indicate a situation in which the non-refractive optical device 101 receives ambient light and is arranged such that the received ambient light is received by the image sensor 120 . As can be appreciated from the embodiments described above herein, not all functional elements shown in FIG. 8 need be present.

Any connection for data transmission may be a physical connection (wired), but may alternatively be wireless and may be based on the transmission of electromagnetic/optical radiation.

The non-refractive optics 101 may be any type of non-refractive optical element as described above herein. In a preferred embodiment, the non-refractive optics may include one or more pinholes. The diameter of the pinhole may be in the range of 50 to 400 μm. Alternatively, as described above, non-refractive optics may be replaced with lenses, which are preferably thin lenses that allow temperature modulation with low computational effort.

The processing unit 9 may be any suitable processing unit known in the art.

Image sensor 120 preferably includes a set of photosensitive elements (pixels) arranged in a 2D matrix that forms the image plane of a camera, such as a CCD sensor or CMOS sensor. The image sensor 120 is arranged to receive a light beam 6 coming through the non-refractive optics 101 . Each light beam 6 will be focused on a subset of these photosensitive elements. Each of these subsets corresponds to the solid angle of one incoming light beam 6 , i.e. both the angle of incidence in the horizontal plane and the angle of incidence in the vertical plane with respect to the ground. Of course, the angles of incidence may also be measured with respect to a non-Earth object, such as a geostationary satellite. As long as both the camera 7 and the survey reflector 1 are held in a fixed position, this subset is static per survey reflector 1 .

In an alternative embodiment, the line sensor may be used in combination with an optical slit rather than a pinhole as the objective. The optical slit, in this embodiment, is oriented essentially perpendicular to the lateral direction of the line sensor. This alternative embodiment may provide a measure of angle in one dimension. To increase the number of dimensions available to be measured, two or more of these devices equipped with line sensors can be arranged in a variety of different orientations. For example, two of these devices can be arranged in a vertical manner, thereby enabling measurements similar to those performed with a 2D matrix sensor. Such a linear sensor arrangement has the advantage of dissipating significantly less power than devices using a 2D matrix sensor.

Optionally, a temperature control system 103 may be provided to reduce the thermal effect on the measurement data. The heat capacity of the non-refractive optics 101 is relatively low compared to the camera 7 using a lens system instead of the non-refractive optics 101 . Thermal stability can be improved by implementing a temperature control system in the form of a thermostat 103 . 8 shows an embodiment with a Peltier element 103 that is reversible (ie configured for both cooling and heating) for non-refractive optics 101 . The Peltier element 103 is connected to a processing unit 9 so that the non-refractive optics 101 is maintained at a predetermined temperature, whereby the temperature is controlled. Alternatively, thermal stability is measured by the design of the camera housing, in particular through and/or within the material used accordingly, and using a model to account for thermal effects during processing of data from the image sensor. can be increased by

Below, some general aspects of the systems described above and methods of operation thereof herein will be summarized.

If the system is equipped with two or more cameras, for example as shown in FIG. 6 , techniques as described herein can be used to measure how far the measuring reflectors 1 , 61 are from the cameras. . This can be done by triangulation measurements if one baseline is known. Measuring the distance between the cameras 7 , 27 , 37 , 47 , 57 , 77 and the survey reflector 1 can also be performed with other distance measurement techniques, such as time-of-flight measurements.

The image sensors 24 , 34 , 44 , 54 , 74 , and 120 convert the received light beam 6 into an image. An image is a set of electronic signals referred to herein as pixel signals. Each pixel signal is generated by one photosensitive element and has a value dependent on the light intensity of the light received by the photosensitive element. Thus, the pixel signal can also be related to the object 3 to which the survey reflector 1 is attached and its surroundings.

The image sensor is positioned such that light entering the camera through the non-refracting element forms a diffraction pattern in the image sensor. The diffraction pattern will vary depending on the nature of the non-refractive element, and will appear as a dark or light area in the image sensor depending on the distance and angle of each pixel of the image sensor to the non-refractive element. By integrating a plurality of data frames each comprising a plurality of pixels, typically at least 100 pixels, high-resolution measurement results can be achieved.

In embodiments using refractive optics such as lenses, the image sensor is preferably positioned such that its photosensitive element is near the focal plane of the lens. In another preferred embodiment, the image sensor 120 is positioned at a location within the focal length of the lens that causes the image to be defocused by a certain amount to bring it out of focus to infinity. In such embodiments, image processing may include super-resolution imaging based on defocusing techniques, thereby enabling sub-pixel resolution. Then 1/100 of a pixel or even better resolution can be obtained.

The processing unit 9 is arranged to receive the pixel signal from the image sensor 120 and store it in the memory 15 . The pixel signal can be stored by the processing unit 9 as a single picture, preferably with a time stamp and/or a position stamp indicating the position of the camera 7 . Preferably, however, the pixel signal is stored by the processing unit 9 as a series of pictures which together form a video, each picture being provided with a time stamp and/or a location stamp indicating the position of the camera 7 . .

The clock 23 provides a clock signal to the processing unit 9, as known to those skilled in the art. The clock signal is used for normal processing of the processing unit 9 . The processing unit 9 may make the time stamp based on this clock signal. However, camera 7 may be equipped with a GNSS unit that receives time signals from satellites, or camera 7 may receive time signals from other suitable sources.

Memory 15 may include various types of sub-memory, such as read only memory (ROM)/flash type memory, that stores appropriate program instructions and data for executing processing unit 9 . The memory may also include a suitable random access memory (RAM) type of memory for storing temporary data, such as data received from the image sensor 120 . Also, the memory 15 may include a cache type memory. Some or all of the sub-memory may be physically located remotely from other components. Further, the processing unit 9 may be arranged to transmit all pixel signals to a remote unit via the electronic networking module(s) 20 for external storage and processing. A local copy of this pixel signal may but need not be stored in the local memory 15 in the camera 7 .

The memory 15 stores initial position data indicating the initial position of the camera 7 . This initial location data may be set using a theodolite and then stored by the user. Also, this initial position data may result from measurements made by the camera 7 itself. For example, the camera 7 may collect a series of pictures from a known “blinking” light source installed at a high air traffic obstacle marker with a well-known location. Such obstacle markers may be placed at a defined vertical distance in tall structures, thereby enabling triangulation. In addition, the memory 15 stores a camera ID that identifies the camera 7 and is used by the processing unit 9 in external communication with other devices to identify itself to other external devices.

Position and/or orientation measurement component 16 may include one or more accelerometers and/or gyrometers/gyroscopes, as known to those skilled in the art. It may also include the GNSS unit mentioned above. These accelerometers and/or gyrometers/gyroscopes measure the movement of the camera itself and derive updated camera position and orientation from these measurements. The updated camera position and/or orientation is then stored in the memory 15 by the processing unit 9 . By doing so, changes in camera position and/or orientation may be taken into account when measuring the position of one or more survey reflectors 1 . The accuracy may be on the order of 1/1000 of a degree. The test showed that the peak-to-peak was 2 milli degrees. Moreover, the 3-axis accelerometer package can also measure the direction of Earth's gravity when at rest. A sufficiently capable 3D gyro package (also at rest) can measure the direction of the Earth's axis of rotation.

The output unit 17 may include one or more sub-output units such as a display and a speaker.

The input unit 19 may include one or more sub-input units such as a keyboard and a microphone. The display and keyboard can be manufactured as two separate touch screens. However, they can also be implemented as a single touch screen.

The electronic networking module 20 includes a Long Term Evolution (LTE) module, an Ethernet module, a WiFi module, a Bluetooth module, a powerline communication module, a low-power wide area network (eg, Lora™ and Sigfox™) module, and a Near Field Communication (NFC) module. It may include one or more of the modules. Any proprietary communication protocol and technology known from the Internet of Things (IoT) may be used.

The at least one light source 102 includes at least one light source, such as a light emitting diode (LED) light source configured to generate light. The processing unit 9 is arranged to control each LED light source so that they generate a light beam.

As shown in FIG. 9 , the camera may be provided with a housing configured to withstand high temperature and/or high pressure environments (eg, deep sea or geothermal activity environments) without introducing significant errors due to deformation of the optical elements. . The housing (which may be used with all cameras 27 , 37 , 47 , 57 , 67A, 67B, 77 described in different embodiments herein) has at least one wall surrounding a void 610 . (600). The image sensor 120 is mounted in the empty space 610 . The housing is closed by a front wall or cover, also referred to herein as the body, provided with a pin hole 102 (or other optical input system). The pin hole 102 is configured to form an image in the sensor 120 as described hereinabove. The first, second and third light sources described above herein may be arranged on or within an outwardly facing front wall or body of the housing to emit their light beams in an outward direction. The housing may further be provided with various additional features and/or elements, for example as appropriate to the particular environment in which the camera will be used.

The basic idea of the device and method of monitoring an object using the device is that either the camera 7 or any of the cameras 27, 37, 47, 57, 67A, 67B, 77 described in other embodiments herein is stationary. It is arranged in a fixed position so that it is in a state. The stop position is then known and stored in the memory 15 accessible by the processing unit 9 in the camera 7 .

All of the survey reflectors 1 , or equivalently, the survey reflectors 21 , 31 , 41 , 51 , 61 , 7 described hereinabove in the various embodiments, or further described herein below and FIGS. 11-15 . When the target units 1100 , 1101 , 1102 , 1103 shown in are installed, they have an initial location that can be stored in the camera's memory 15 .

Thus, when the system is started, the camera knows all of the initial positions of the survey reflectors corresponding to the initial positions and orientations of the object 3 to which they are attached.

The processing unit 9 is arranged to calculate the initial stereoscopic angle of incidence of each reflected light beam 6 . That is, the received reflected light beam is imaged, via non-refractive optics, onto one or more photosensitive elements of the image sensor 120 . The processing unit 9 determines which of these photosensitive elements is and sets the stereoscopic incidence angle of the corresponding light pulse. Techniques for doing so are known to the person skilled in the art and need not be described in further detail herein.

When the object 3 is stable, ie not moving, the positions of all survey reflectors 1 are also stable. Consequently, the stereoscopic angle of incidence of each reflected light beam at the image sensor of the camera is fixed. However, as soon as the object 3 or part of the object moves, this stereoscopic angle of incidence of the reflected light beam 6 changes. The processing unit 9 is arranged to calculate this change in solid angle for each light beam 6 .

10 shows an example of successive steps of image processing according to an embodiment of the present invention.

The camera 7 receives the reflected light beam 6 from the survey reflectors 1 , 1100 , 1101 , 1102 , 1103 , 1401 , 1402 , 1403 which is projected on the image sensor 120 . Figure 10 shows the flow of a process according to an embodiment performed by the processing unit 9 for extracting the relevant survey reflector data. This flow of process applies equally to any of the embodiments described above herein. 10 illustrates a basic process, additional details may be added to one or more process steps and/or as specifically described herein above and/or as understood by one of ordinary skill in the art. As such, it should be understood that additional process steps may be added to further optimize the method.

The first step 1001 in the process is to record or capture at least two, but preferably many, image frames or raw data frames in sequential order. Each image frame is essentially a 2D array of light values. By capturing a sequence of image frames, a 3D matrix of light values is formed. The axes in the 3D matrix are X, Y and time T. In one embodiment, a sequence of 100 images is captured at 1/60 second intervals.

In step 1002, digital processing is applied to the sequence of image frames to enhance data or coded light beams related to one particular light source, while suppressing the effects of other light received by the image sensor, as described herein above. can The output of this process is a 2D image. Multiple light sources with different and unique codes can be processed using the same 3D matrix of light values over time, each will produce a unique 2D image.

In step 1002a, the processed 2D image may include both (diffuse) reflected light of the environment and reflections from a survey reflector of a divergent light beam emitted by the one or more first light sources.

In step 1002b, the 2D processed image associated with the light emitted by the second light source includes (diffuse) reflected light of the environment, as described herein above with reference to FIG. 3 , but the reflected light to the survey reflector is may not be included.

In step 1002c, which may be optional, the processed 2D image may equally include (diffuse) reflected light from both the environment and the survey reflectors, but this may include one or more light sources, e.g., having a different location than the location at 1002a. Since it originates from the third light source, the position of the survey reflector in the 2D image will be slightly shifted relative to the image obtained in step 1002a.

In step 1003, the two 2D images obtained in steps 1002a and 1002b, respectively, are subtracted from each other to reveal only the reflected light of one particular light source by a survey reflector. By subtracting the image obtained in step 1002b and optionally the image obtained in step 1002c from the image obtained in step 1002a, the effect of ambient light and diffusely reflected light of other light sources is suppressed while suppressing the effect of light emitted by the first light source from the survey reflector. Reflection can be improved. The result is a single 2D image that substantially represents only the reflection of the first diverging light beam at the survey reflector, while other effects are suppressed.

In step 1004, a position of a survey reflector and/or a movement of one or more of the monitored survey reflectors is determined. A specific light source, for example light emitted by the first light source or light with a specific coding, eg a first coding, reflected from a survey reflector is, for each survey reflector, preferably a plurality of pixels and non-refracting In the case of optics, it creates features or blobs that contain diffraction patterns. By correlating the feature or pattern in the 2D image obtained in step 1004 with a predetermined (eg, default) feature or diffraction pattern and/or a previously measured feature or diffraction pattern, the position of the survey reflectors and/or any of these Movement of one or more survey reflectors may be determined.

In step 1005, the acquired data, ie the exact 2D coordinates of each of the reflectors, are made available to other processes. This may include additional processes for correcting errors such as camera movement, temperature compensation, etc., processes for estimating distances based on two light sources, storage of data, display of data, and the like.

11 illustrates a target unit 1100 according to an embodiment. The target unit 1100 comprises a plurality of survey reflectors 111 arranged in the same plane, indicated by dashed lines p1 or p2 . As shown in FIG. 12A , the survey reflector 111 may advantageously be the survey reflector 21 , 31 , 41 , 51 , 61 or 71 described above herein. As shown in Fig. 11, the plurality of survey reflectors 111 are symmetrically arranged around the center of symmetry where the survey reflectors 111c are arranged. In the illustrated embodiment, each survey reflector except those located at the edge of the array has six nearest neighbors. In other words, the reflectors are arranged in shifted or offset rows, and the rows may have different numbers of reflectors. The survey reflectors 111 are all preferably substantially identical. The plurality of survey reflectors 111 may be arranged or mounted to a holder 110 that may be mounted on a standard or tripod arranged on the ground, or fixed to an object or structure, such as the object 3 shown in FIGS. 1A-1A . have. The holder 110 is advantageously non-reflective and opaque to the light emitted by the survey camera 7 .

The front surface of the survey reflector that receives the incoming light may be circular, whereby the hexagonal arrangement provides the most efficient arrangement of the reflectors, as shown in FIG. 11 .

The plurality of target units 1100 shown in FIG. 11 may advantageously form part of any one of the systems described herein above with reference to FIGS. 2 to 4 , 5a , 6 and 7 .

Fig. 12a shows a section along a-a of Fig. 11; As can be seen, the object unit 1100 includes a plurality of survey prisms 111 . These can advantageously be represented here by the surveying prisms 21 , 31 , 41 , 51 , 61 , 71 described above.

12B and 12C show alternative embodiments 1102 , 1103 of subject unit 1100 . This embodiment differs from the embodiment of FIG. 12A by the type of survey reflector used. However, even in this embodiment, the survey reflectors may be arranged in the pattern shown in FIG. 11 .

12B shows an object unit 1102 comprising a plurality of convex mirrors 11102 . These may be similar to the survey reflector 5102 shown in FIG. 5D .

12C shows an object unit 1103 comprising a plurality of concave mirrors 11103 . These may be similar to the survey reflector 5103 shown in FIG. 5E .

13A-13E show a dense arrangement similar to that of FIG. 11 for a different number of individual survey reflectors 141 . In the illustrated embodiment, the survey reflector has a circular base that directs the incoming light beam. However, similar arrangements are possible with other shaped bases.

In the embodiment shown in FIGS. 13A-13E , an arrangement is shown for an object unit comprising 3, 7, 19, 37 and 61 survey reflectors, respectively. Increasing the number of reflectors generally increases the working distance of the system. As can be seen, the individual reflectors are arranged in an array having a center of rotation and/or mirror symmetry such that the intensity of the reflected light is substantially equal in different directions of the cross-section of the reflected light beam. However, in certain applications, rectangular arrays or arrays of reflectors of only one line are also possible.

14a to 14c schematically show a packing arrangement of a prism 141 having a triangular base. As can be seen, they can be arranged such that the base sides of neighboring prisms are adjacent to each other. Fig. 15 schematically shows the arrangement of Fig. 14a from the rear side;

It will be apparent to those skilled in the art that the scope of the present invention is not limited to the examples discussed above, and that various modifications and changes can be made therein without departing from the scope of the invention as defined in the appended claims. While the present invention has been shown and described in detail in the drawings and description, such drawings and descriptions are to be regarded as illustrative only or illustrative rather than restrictive. The present invention is not limited to the disclosed embodiments, but includes any combination of disclosed embodiments that may be advantageous.

Modifications to the disclosed embodiments can be understood and effected by those skilled in the art in practicing the claimed invention from a study of the drawings, description, and appended claims. Features of the foregoing embodiments and aspects may be combined so long as the combination does not result in an obvious technical conflict.

Claims (28)

A system for monitoring a survey reflector (1; 21; 31; 41; 51; 5101; 5102; 5103; 61; 71) arranged at a plurality of positions on an object (3), said system comprising:
A camera (7; 27; 37; 47; 57; 67A, 67B; 77) comprising:
One or more first light sources 22; 321; 42; 521; 72 for emitting first diverging beams 5; 25; 351; 45; 551; 75, respectively, having a solid angle Ω1 greater than zero. 102) - the one or more first light sources are arranged such that a field in a space corresponding to at least 10% of a field of view of the camera is illuminated by the one or more first light sources;
an image sensor 24; 34; 44; 54; 74; 120 for receiving a reflected light beam 26; 361; 46 comprising reflection of the first divergent beam by the plurality of survey reflectors and for providing image sensor data ); and
body 28; 38; 48; 58; 78, provided with an optical entry system 23; 33; 43; 53; 73, said body having a first side facing the interior space of said camera and said interior space wherein the image sensor is located within the interior space, the at least one first light source is located at the second side of the body, and wherein the at least one first light source is disposed from the optical input system. arranged at the first distance (D1; d) -
The camera comprising; and
a processing unit (9; 29; 79) configured to process said data
including,
The processing unit determines a position of each of the survey reflectors from the data, and based on a comparison of the determined position of each survey reflector with a previously determined position of the survey reflector of the at least one of the plurality of survey reflectors. A system configured to detect movement. According to claim 1,
wherein the optical input system comprises a non-refractive optical element (101) forming an objective of the camera. 3. The method of claim 1 or 2,
A field in the space corresponds to at least 50% of the field of view of the camera, and preferably, the field in the space is substantially equal to or greater than the field of view of the camera. camera. 4. The method according to any one of claims 1 to 3,
and the processing unit is further configured to apply a first code to the first divergent beam by modulation of the first divergent beam, and to apply a filtering technique during image processing of the recorded data. 5. The method of claim 4,
one or more second light sources (322) emitting a second divergent beam (352), the one or more second light sources arranged at a second distance (D2) greater than the first distance from the optical input system and the second distance is such that a reflection 362 of the second divergent light beam from the survey reflector does not enter the camera via the optical input system, and the processing unit sends a second code to the second divergent beam. and wherein the second code is different from the first code. 6. The method according to claim 4 or 5,
one or more third light sources (522) configured to emit a third divergent beam (552), wherein the one or more third light sources are at a third distance from the optical input system substantially similar to the first distance (d) arranged in (d), wherein the processing unit is further configured to apply a third code to the third diverging beam, wherein the third code is different from the first code, and when the second code is used, the different from the second code, the system. 7. The method according to any one of claims 1 to 6,
wherein the processing unit is further configured to apply a command code to the first divergent beam, the command code comprising an instruction, information and/or request to be transmitted to a survey reflector. 8. The method according to any one of claims 1 to 7,
A survey reflector identification unit 761 provided to or included in the survey reflector, wherein the survey reflector identification unit comprises:
a light receiver 71 for receiving the first divergent beam;
a microcontroller (719) coupled to the light receiver; and
an identification unit light emitter 712 configured to emit a unique identification signal in response to the microcontroller receiving a command
comprising, a system. A method for monitoring a plurality of survey reflectors (1; 21; 31; 41; 51; 5101; 5102; 5103; 61; 71) provided at locations on an object, said method comprising:
at the first camera position,
a first diverging beam 5; 25; 351 having a solid angle greater than zero towards the plurality of survey reflectors by each of one or more first light sources 22; 321; 42; 521; 72; 102; emitting 45; 551; 75, wherein the plurality of survey reflectors are irradiated substantially simultaneously by the at least one first diverging beam, the at least one first light source maintained in a substantially fixed position; ; and
recording, by an image sensor (24; 34; 44; 54; 74; 120), data representative of a reflected light beam comprising reflection of the first divergent beam by the plurality of survey reflectors;
monitoring the locations by and
determine a position of each survey reflector from the data, by image processing of the data, and based on a comparison of the determined position of each survey reflector with a previously determined position of the survey reflector, at least one of the plurality of survey reflectors detecting movement of the survey reflector;
A method comprising 10. The method of claim 9,
Applying a first code to the first diverging beam by modulation of the first diverging beam, and applying a filtering technique when image processing the data so that the light resulting from the reflection of the first beam is directed to another light source and/or or differentiating from other reflections. 11. The method of claim 10,
a body (28; 38; 48; 58; 78) provided with an optical entry system (23; 33; 43; 53; 73) allowing passage of light, said body having a first side and a second side wherein the first side faces the interior space of the camera and the second side faces away from the interior space so that the image sensor is arranged in the interior space of the body and the at least one first light source is directed toward the interior space of the body. arranging the body to be arranged on the second side;
arranging the one or more first light sources at a first distance (D1, d) from the optical input system;
arranging one or more second light sources 322 at a second distance D2 greater than the first distance, wherein the second distance allows reflection of the second divergent light beam from the survey reflector through the optical input system to the camera emitting a second divergent beam by each of said one or more second light sources; and
applying a second code to the second divergent beam by modulation of the second divergent beam, wherein the second code is different from the first code
A method further comprising: 12. The method of claim 11,
wherein the optical input system comprises a non-refractive optical element forming a camera objective. 13. The method according to any one of claims 10 to 12,
generating (1002a) a first image from the reflected light having the first code;
generating (1002b) a second image from the reflected light having the second code; and
subtracting (1003) the second image from the first image and determining (1004) the position and/or movement of one or more of the survey reflectors from the resulting image.
A method further comprising: 14. The method according to any one of claims 10 to 13,
providing one or more third light sources 522, each emitting a third divergent beam 552, the one or more third light sources being at a first distance d from the optical input system at which the one or more first light sources are arranged ) arranged at a third distance d substantially similar to and, if the second code exists, it is different from the second code; and
Calculate the distance between the camera and the survey reflector from the first point p1 on the image sensor resulting from the reflection from the survey reflector of the light emitted from the first light source and from the survey reflector of the light emitted from the third light source determining from the distance between the second point p2 on the image sensor resulting from the reflection of
A method further comprising: 15. The method according to any one of claims 9 to 14,
monitoring the positions at a second camera position positioned away from the first camera position, wherein a first viewing line between the first camera position and a reference survey reflector is between the second camera position and the reference oriented obliquely with respect to a second line of sight between the survey reflectors; and
determining three-dimensional coordinates of the survey reflector based on the monitoring at the first camera position and the second camera position;
further comprising,
and the monitoring at the second camera position is performed similarly to the monitoring at the first camera position. A system for monitoring a survey reflector (1; 21; 31; 41; 51; 5101; 5102; 5103; 61; 71) arranged at a plurality of positions on an object (3), said system comprising:
a camera (7; 27; 37; 47; 57; 67A, 67B; 77) configured to monitor the survey reflector,
one or more first light sources 22; 321; 42; 521; 72; 102 for emitting first divergent beams 5; 25; 351; 45; 551; 75, each having a solid angle greater than zero;
one or more second light sources 322 for emitting a second diverging beam 352 each having a solid angle greater than zero;
an image sensor (24; 34; 44; 54; 74; 120) for receiving a reflected light beam comprising reflection of the first divergent beam by the plurality of survey reflectors and for providing data; and
body 28; 38; 48; 58; 78, provided with an optical entry system 23; 33; 43; 53; 73, said body having a first side facing the interior space of said camera and said interior space having a second side facing away from, the image sensor located within the interior space, and the first and second light sources located on the second side of the body;
The camera comprising; and
a processing unit (9; 29; 79) configured to process said data
including,
The one or more first light sources are arranged at a first distance D1, d from the optical input system, and the one or more second light sources are arranged at a second distance D2 greater than the first distance from the optical input system. arranged,
the processing unit is configured to apply a first code to the first beam and to apply a second code to the second beam, wherein the second code is different from the first code;
the first and second codes are applied by modulation of the first and second diverging beams;
and the processing unit is configured to apply a filtering technique during image processing of the recorded data. 17. The method of claim 16,
the at least one first light source and the at least one second light source illuminate a field in space corresponding to at least 10% of the field of view of the camera such that the first and second beams are emitted toward a plurality of survey reflectors substantially simultaneously arranged to do so. A method of monitoring positions on an object, the method comprising:
providing a plurality of survey reflectors (1; 21; 31; 41; 51; 5101; 5102; 5103; 61; 71) on said object, each survey reflector being provided at one of said locations;
the locations,
a first divergent beam 5; 25; 351; 45; 551 having a solid angle greater than zero toward the plurality of survey reflectors by each of one or more first light sources 22; 321; 42; 521; 72; 102; 75) releasing;
emitting, by each of one or more second light sources (322), a second diverging beam (352) having a solid angle greater than zero toward the plurality of survey reflectors; and
recording, by an image sensor (24; 34; 44; 54; 74; 120), data representative of a reflected light beam comprising reflection of the first divergent beam by the plurality of survey reflectors;
monitoring by; and
determine a position of each survey reflector from the data, by image processing of the data, and based on a comparison of the determined position of each survey reflector with a previously determined position of the survey reflector, at least one of the plurality of survey reflectors detecting movement of the survey reflector;
including,
The method further comprises applying a first code to the first diverging beam and applying a second code to the second diverging beam, wherein the second code is different from the first code; and a second code is applied by modulation of the first and second diverging beams;
wherein the image processing includes applying a filtering technique, such as filtering data related to reflections of the first divergent beam and/or the second divergent beam. 21. The method of claim 20,
The image sensor is located in the interior space defined at least in part by a body 28; 38; 48; 58; 78 having a first side facing the interior space of the camera and a second side facing away from the interior space. wherein said body comprises an optical entry system (23; 33; 43; 53; 73), said first and second light sources being located on a second side of said body;
the first light source is arranged at a first distance D1 from the optical input system, the second light source is arranged at a second distance D2 greater than the first distance from the optical input system,
the first distance allows reflection of the first divergent beam from the survey reflector to pass through the optical input system, and the second distance allows reflection of the second divergent beam from the survey reflector to pass through the optical input system. The way, which does not make it possible to pass. 20. The method according to any one of claims 18 to 19,
generating (1002a) a first image from the reflected light having the first code;
generating (1002b) a second image from the reflected light having the second code; and
subtracting (1003) the second image from the first image and determining the position and/or movement of one or more of the survey reflectors from the resulting image.
A method further comprising: Use with a system according to any one of claims 1 to 8, 16 and 17 and/or in a method according to any one of claims 9 to 15 and 18 to 20 A survey object unit (1100; 1101; 1102; 1103) for 5102; 5103; 61; 71; 111; 11101; 11102; 11103). 22. The method of claim 21,
the survey reflectors are arranged in an array, and one of the survey reflectors (111c) is arranged at the center of the array, the center representing a point of symmetry of the array. 23. The method of claim 21 or 22,
and the survey reflectors are arranged in a hexagonal array pattern. 24. The method according to any one of claims 21 to 23,
wherein each survey reflector has a surface configured to receive an incoming light beam, the surface being substantially circular. 25. The method according to any one of claims 21 to 24,
Said plurality of surveying reflectors is realized by a plurality of surveying prisms (21; 31; 41; 51; 61; 71; 111), said prisms preferably substantially identical, of said prisms configured to receive an incoming light beam. the surface is arranged in said one single plane. 25. The method according to any one of claims 21 to 24,
The plurality of survey reflectors is embodied by a plurality of hollow mirrors 5102; 5103; 11102; 11103, each having a central point c, the hollow mirrors preferably being substantially identical, and the a center point is arranged in said one single plane (p1, p2). 27. The method according to any one of claims 21 to 26,
wherein the plurality of survey reflectors comprises 13 to 35 reflectors. 18. The method according to any one of claims 1 to 8, 16 and 17,
28. A system, further comprising a plurality of units to be surveyed according to any one of claims 21 to 27.

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